The present invention relates to a vehicle leveling system.
There have been proposed various road vehicle leveling systems for adjusting the height of the body or sprung mass of a road vehicle with respect to the ground. One type of such leveling system employs a pressurized gas as a leveling medium. The pressurized gas is supplied from a gas pressure generator unit such as a compressor to a pneumatic leveling unit through a valve mechanism which controls the pressurized gas as it is fed into or discharged from the pneumatic leveling unit. The leveling system of this design is disclosed in U.S. Pat. Nos. 3,881,743 and 4,396,202.
As described in the above U.S. Patents, the pneumatic leveling unit is normally constructed wholly or partly as a vehicle suspension spring since the pneumatic leveling unit is essentially analogous in structure to an air spring. The leveling system also has a valve device and its control device for delivering the pressurized gas into and discharging it from the pneumatic leveling unit. The better the functions of the valve device and the control device, the more easily and conveniently the leveling system can be operated. The conventional leveling systems remain to be improved for easier and more convenient operation.